The versatility and performance of newer muscle cars such as the FORD MUSTANG permit owners to use one vehicle for multiple purposes. Often the same vehicle used to carry groceries home from the supermarket is used for racing applications on the weekend. Owners will often modify their vehicle to make it more competitive in their chosen form of racing. One of the most modified areas of a vehicle for racing applications is the suspension.
Front suspension tuning can be one of the most critical aspects of getting a vehicle to handle properly for either street or racing applications. Unfortunately, front suspensions that are modified exclusively for racing typically will not work properly for street driving, and street suspensions typically do not work well for racing. One of the biggest challenges for a muscle car owner who races his vehicle has been to balance the vehicle for both uses.
The front wheel of a vehicle has three main alignment angles: camber, caster, and toe. Camber is the angle at which the top of the tire is tilted inwardly or outwardly, as viewed from the front of the car. If the top of the tires lean toward the center of the car you have negative camber. If the top of the tires are tilted outward you have positive camber. Typically, as the tires are turned left and right, the camber changes slightly because the pivoting points for the tires are not vertical as viewed from the side. Adjusting camber can have a dramatic affect on the cornering characteristics of a vehicle. For example, an oval track racer will often race with negative camber on the right side of the vehicle and positive camber on the left side of the vehicle. A drag racer will often race with neutral or slightly negative camber on both sides of the vehicle and a street vehicle will typically have camber set at zero or perpendicular to the street surface.
Caster is the angle at which the pivot points for tires are tilted, as viewed from the side. Caster is best understood by imagining an axis running through the uppermost wheel pivot and extending through the lowermost pivot. From the side, if the top of the axis tilts toward the back of the car you have positive caster, if the axis line tilts toward the front of the car you have negative caster. If a vehicle has positive caster, the uppermost pivot is behind the lower pivot and this causes the tire to tilt in more at the top as the tire is steered inward (camber gain).
Changing caster primarily affects four things: high speed stability, camber gain, bump steer characteristics, and relative corner weights (wedge). Increasing caster generally increases straight line directional stability. This is good for an application such as drag racing, however, other parameters such as bump steer and wedge may be adversely affected making handling for applications such as street driving or road racing unacceptable. Excessive caster settings will increase required steering effort, cause excessive tire wear and reduce braking ability. Negative caster requires less steering effort, but directional stability is adversely affected. Some racing applications may require different caster settings on each side of the vehicle. For example, oval track racers often run more positive caster on the right side wheel than the left. The caster split helps pull the car down into the turn, helps the car turn in the center of the turn, and helps the car maintain traction exiting the turn.
Accordingly, what is lacking in the art is a suspension tuning kit for vehicles with struts. The suspension tuning kit should achieve objectives such as providing: quick adjustment, increased suspension rigidity, increased range of adjustability and reliable performance. The suspension tuning kit should include packaging flexibility for installation on various vehicle configurations including retrofitting existing vehicles with minimal modification of the original suspension system. The suspension tuning kit should facilitate independent caster and camber adjustment of each front wheel across the extended range. The suspension tuning kit should facilitate quick suspension changes to allow a vehicle to be driven to a racetrack, converted to a race setup, and thereafter quickly converted back to a street driving setup for the trip home.